In science, number of atoms in (something), such as 'one human', 'the earth', 'the sun', 'the galaxy', 'the universe', among other varieties, is a popular search query. The following table lists some of these atomic counts. [1] The third column, Exp, shows the old-fashioned calculator shorthand symbol for large numbers, in which E is short for exponent, in the sense that, for instance, E9 is short for 10E9 which is short for  10^9 \,.

#NameNumber written out
ExpNumber of atoms in





1one1
 H \,
2two2
 H_2 \,
3three3
 H_2 O \,
 10^2 \,hundred100E2
 10^3 \,thousand1,000E3
 10^6 \,million1,000,000E6
 10^9 \,billion1,000,000,000E9(ten) bacteria molecules
 10^{12} \,trillion1,000,000,000,000E12
 10^{15} \,quadrillion1,000,000,000,000,000E15(ten) pre-aquatic worms
 10^{18} \,quintillion1,000,000,000,000,000,000E18
 10^{21} \,sextillion1,000,000,000,000,000,000,000E21(one) small fish
 10^{24} \,septillion1,000,000,000,000,000,000,000,000E24Avogadro's number
 10^{27} \,octillion1,000,000,000,000,000,000,000,000,000E27(one) human molecule (person)
 10^{30} \,nonillion1,000,000,000,000,000,000,000,000,000,000E30
 10^{33} \,decillion1,000,000,000,000,000,000,000,000,000,000,000E33
 10^{36} \,undecillion1,000,000,000,000,000,000,000,000,000,000,000,000E36
 10^{39} \,duodecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000E39
 10^{42} \,tredecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000E42
 10^{45} \,quattuordecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E45
 10^{48} \,quindecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E48
 10^{51} \,sexdecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E51(one) earth molecule (the earth)
  10^{54} \,septendecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E54
 10^{57} \,octodecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E57(one) sun molecule (the sun)
 10^{60} \,novemdecillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000E60
 10^{63} \,vigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000
E63
 10^{66} \,unvigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000
E66the milky way galaxy
 10^{69} \,duovigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000
E69
 10^{72} \,tresvigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000
E72
 10^{75} \,quattuorvigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000
E75
 10^{78} \,quinquavigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000
E78
 10^{81} \,sesvigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000
E81the observable universe
 10^{84} \,septemvigintillion1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000
E84






Multiverse
At the high end of the hypothetical estimates and speculative theories is the idea that the observable universe is connected to other 'parallel universes', possibly via wormholes (or other contrivances), such that the total set of parallel universes make up what is called the 'multiverse', of which one estimate indicates that at most there could be the following number of parallel universes: [2]

 10^{10^{16}} \, = number of parallel universes

which multiplied by the number of estimated atoms in our observable universe, indicates that there could be the following number of atoms in the multiverse:

 10^{81} \cdot 10^{10^{16}} \,

or, using round-off, about:

 10^{10^{18}} \,= number of atoms in the multiverse (hypothetical)

Human molecule
In the English textual context, one would say that one person or one human molecule is comprised of an octillion atoms, of twenty-six types of 'active' elements.

References
1. Thims, Libb. (2008). The Human Molecule (preview) (Google Books). Morrisville, NC: LuLu.
2. Zyga, Lisa. (2009). “Physicists Calculate the Number of Parallel Universes”, Physorg.com, Oct. 16.

External links
Names of larger numbers – Wikipedia.
Number of atoms in the human body – NumberOf.net.

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